Another Cause of Obesity: Bacteria?

Just the other day, I came across an article on the Times Magazine website, highlighting new research that seems to explain certain cases of obesity.

“If you have ever fought the battle of the bulge, then you are all too familiar with its key players: diet, exercise and your genes. The less you move (calories out) and the more you eat (calories in), the more fat you gain – an equation that may be heavily influenced by your particular genes.

But scientists have long known that these three factors do not adequately explain every case of obesity, and now researchers are discovering increasingly convincing evidence of another important contributor to body weight, one that until recently has been almost completely ignored: the bacteria that live in your gut. […]

The new study builds on past research, in mice, that has suggested that heavy bodies may have a different make-up of gut bugs than thin ones: the gut microbiota of obese mice has been shown to have significantly more of one main type of bacteria called Firmicutes, and fewer of another kind called Bacteroidetes (both types populate human guts as well); in normal mice, the distribution is the opposite. […]

Jeffrey Gordon at Washington University in St. Louis, who conducted the past research, experimented again with mice for the new paper. This time, however, he and his team used human microbiota to colonize mice guts and then fed the rodents the equivalents of typical human diets to see how their microbes – and their weight – might change.”